Li-ion batteries in portable electronic devices typically undergo different charging, discharging and storage routines based on their use. Batteries that employ Li-ion cell chemistry may produce gas when they are improperly charged, shorted or exposed to high temperatures. This gas can be combustible and may compromise the reliability and safety of such batteries. A current interrupt device (CID) is typically employed to provide protection against any excessive internal pressure increase in a battery by interrupting the current path from the battery when pressure inside the battery is greater than a predetermined value. The CID typically includes first and second conductive plates in electrical communication with each other. The first and second conductive plates are, in turn, in electrical communication with an electrode and a terminal of the battery, respectively. The second conductive plate separates from (e.g., deforms away or is detached from) the first conductive plate of the CID when pressure inside the battery is greater than a predetermined value, whereby a current flow between the electrode and the terminal is interrupted.
Generally, however, CIDs known in the art activate at a relatively high pressure, for example, at an internal gauge pressure greater than about 15 kg/cm2. Typically, when any excessive internal pressure increase that triggers such CID activation occurs, the internal temperature of the battery is also relatively high, causing additional safety issues. High temperatures are a particular concern in relatively large cells, such as cells larger than “18650” cells (which has an outer diameter of about 18 mm and a length of 65 mm).
Therefore, there is a need for CIDs for batteries, particularly relatively large batteries, that can reduce or minimize the aforementioned safety issues.